San Miquel de Allende trip from Zihuatanejo

Has anyone taken the bus from Zihuatanejo to Celaya and then a bus/taxi from Celaya to San Miquel de Allende?
I don't want to drive.
Flying is an option but it seems like a lot of moving parts for one day.
I saw this bus trip into Celaya from Zihuatanejo -about 5 1/2 hrs -and then another hour from Celaya to SMA by taxi. Wondering if anyone has done it? Thanks!

Celaya, is kind of an armpit. Check other routes and try to avoid it if you can.

D